Indicator mechanism



Ot.5,1 943. K, EMDE 2,330,818

INDICATOR MECHANISM 1 Filed Sept. 20, 1941 3 Sheets-Sheetl Oct. 5, 1943.K. EMDE INDICATOR MECHANISM Filed Sept. 20, 1941 3 Sheets Sheet 2 Two wvilllw I Oct. 5, 1,943. K. EMDE INDICATOR MECHANISM Filed Sept. 20, 19413 Sheets-Sheet 3 Patented Oct. 5, 1943 INDICATOR DIECHANISM Kurt Emde,Itasca, 11]., assignor to Zenith Radio Corporation, Chicago, 111., acorporation of Illinois Application September 20, 1941, Serial No.411,760

7 Claims.

This invention relates to indicator mechanism, and more particularlyconcerns indicator mechanism adapted to selectively display diiferentindicator scales to be used in theadjustment of radio apparatus.

The principal object of the invention is to provide indicator mechanismwhich is particularly useful in accomplishing what .is known as bandspreading, in that it arranges for the use of an indicator scale ofsuitably extensive area for each of the several frequency bands includedwithin the tuning range of all wave" radio apparatus, which arrangementprovides for maximum band spread and also for more accurate adjustmentof the apparatus. Another object of the invention is to provideindicator mechanism employing a plurality of indicator scales in whichone only of suchscales may be viewed at a time, thus avoiding anypossibility oLconfusion in the employment thereof during adjustment ofthe apparatus. A further object of the invention is to provide indicatormechanism of the aforesaid character connected with the usual frequencyband switch so that the proper indicator scale will be brought intoservice automatically and coincidently with the adjustment of the radioapparatus for operation within any selected one of several frequencybands. While the invention has been shown and will be described asembodied in tuning indicator mechanism for "all wave radio receivingsets, it is to be understood that it is not in any sense limitedthereto.

In the drawings,

Figure 1 is a vertical fore-and-aft sectional view of indicatormechanism embodying my invention as applied to the tuning devices ofradio apparatus;

Fig. 2 is a sectional plan view of the indicator mechanism, taken uponthe line 2-2 of Fig. 1: Fig. 3 is a fragmentary view, illustrating adifferent adjustment of certain parts of the indicator mechanism shownand viewed as in Fig. 1;

Fig. 4 is a fragmentary perspective detail view, upon a slightlyenlarged scale, showing parts of the indicator mechanism of Fig. 3 inthe positions illustrated in Fig. 1; and

Fig. 5 is a fragmentary sectional view, taken ited number of selectedportions thereof, embracing several of what are termed the short wave,or high frequency, bands as well asthe broadcast band of much lowerfrequencies. Such sets usually employ a plurality of inductancewindings, corresponding to the several selected portions of the radiofrequency spectrum, and an adjustable band switch for-selectivelythrowing them into and out of circuit connection with a single variablecapacitance unit, or tuning condenser. As is well known to thosefamiliar with such apparatus, tuning condensers having suflicientmaximum capacity for tuning in the lower frequencies of the broadcastband must be very carefully and accurately adjusted when employed fortuning in the higher frequencies of the short wave bands. Operatingmechanism has been provided for effecting this careful and accurateadjustment, one arrangement of which is shown herein as comprising astep-down transmission connecting the manually adjustable tuning knobwith the rotor-shaft of the condenser, and a step-up transmissionconnecting the rotor-shaft of the condenser with the tuning indicator,so that a precise and minute adjustment of the condenser may be effectedby manual operation of the tuning knoband such adjustment accuratelyregistered by the tuning indicator in a readily observable manner.

In many of the indicator mechanisms in use upon all wave" radioreceiving sets, the different indicator scales provided for registeringthe adjustments of the variable capacitance unit are quite limited inextent, and the wide ranges of frequencies covered thereby, particularlyby those scales for use with the short wave bands, cannot be indicatedthereupon for lack of space, excepting in a general way. As a result, inthe short wave bands, where the tuning adjustments require the greaterdegree of care and accuracy, the closely arranged divisions of theindicator scales represent such wide differences in frequencies as to beof little practical value. Another objectionable feature of themulti-scale indicator mechanisms in general use upon all wave radioreceiving sets is that, even where scale-identifying indicia isprovided, the display of a number of indicator scales requiring thevisual selection of the one to be followed for a particular band offrequencies is confusing to the operator.

The present indicator mechanism comprises a plurality ofinterchangeable, longitudinally extending, indicator scales havingdifferent scale arrangements displayed thereupon. I prefer to displaybut one frequency band upon each of the indicator scales and to spreadthe scale arrangements so that the divisional markings thereof may beeasily observed and followed in the adjustment of the apparatus, but Idesire to be not limited to any particular scale arrangement. It will beseen that but one indicator scale is viewable at a time, and that theadjustment of the bandswitch to condition the apparatus for operation ina selected frequency band will automatically bring the proper indicatorscale into view. I thus obtain a much greater band spread and avoid thepossibility of any confusion in the use of the difierentscalearrangements.

Considering, first, the tuner and indicator operating mechanism, andreferring to Figures 1 and 2 of the drawings, l indicates the chassis ofthe radio receiving apparatus upon which is fixedly supported a variabletuning condenser 2, having the usual stator-plates 3 and rotor-plates 4,and the adjusting shaft 5 upon which the rotor-plates 4 are secured.Also fixedly supported upon chassis I is the framework of the indicatormechanism, comprising the base-plate 6, the end-parts of which areupwardly ,turned to form vertical brackets I and 8, and a pair ofbearing-plates 9 and H] which are respectively secured, as by screws ll,one to each of the brackets I and 8.

The upper end-parts of brackets I and 8 bend outwardly at an obliqueangle, as shown at l2 and I3 and support respective pulleys l4 and I5,and bearing-plates 9 and II] are each formed with an upwardly extendingarm, such as l6 (Figure 1), the upper end-parts of which bend inwardly,as at I! and I8, and support respective pulleys l9 and 20.

A comparatively large pulley 2|, the radius of which is considerablygreater than that of the rotor-plates 4, is secured upon shaft 5'and isconnected by a cord-belt 22 with an intermediate shaft 23, around whichthe cord-belt may be Wound a turn or more to obtain traction.Intermediate shaft 23 is rotatably supportedin the "vertical sides24'and 25 of a drop-frame 26 (Figure 1-) which is secured to and dependsfrom the top-ofchassis l, and a relatively large pulley 21 is secureduponthis shaft 23 and connected by a belt 28 with a smaller pulley 29formed as the hub of a fiy-wheel 30 secured upon shaft 3|. Shaft 3| isrotatably supported in the side 24 of drop-frame 26 and in the verticalfront wall 32 of chassis I, passing through a bearing 33 therein andextending through the front wall 34 of the casing, and is provided withtheusual manual tuning knob'35 fixed upon the outer end thereof. Thedriving connections just described constitute the step-down transmissionto which I have referred as connecting the tuning knob with therotor-shaft of the condenser.

. The tuning indicator comprises a pointer 36 which projects downwardlyfrom a saddle 31 slidably supported upon ,a horizontal guide-bar 38.

Guide-bar 38 extends longitudinally across the framework of theindicator mechanism, slightly forward .of-. the.;-1. pW -rdly extendingarms l6 of bearing-plates9 and=| 0, and is rigidly supported uponsaid-framework by its rearwardly bent ends 39 and 4,0, whicharerespectivelysecured, as by othe upwardly "extending arms l6. Asherein shown, the pointer 36 and saddle 31 may be formed as a one-pieceunit and the movement thereof along the guide-bar 38 'etfectedby acord-belt 42, which is passed about pulley 2|, over pulleys l4, l5, l9and 20, and attached to saddle 31 in the manner illustrated Ill2,380,818

in Figure 2. Preferably, the cord-belt 42 is a continuation of cord-belt22 and the ends thereof are attached to take-up means carried uponsaddle 31, such as the pair of springs 43, but separate cord-belts mayof course be used and different take-up means employed, if desired. Theradius of pulley 2| being considerably greater than that of therotor-plates 4, this belt connection of saddle 31 with pulley 2|provides a very simple form of step-up transmission to which I havereferred as connecting the rotorshaft of the condenser with the tuningindicator. I

Continuing to refer to Figures 1 and 2, and considering, now, thearrangement and construction of the indicator scales and of themechanism for effecting their selective employment to bring the properone into service for tuning in the frequency band for which theapparatus may be selectively conditioned, it will be observed that thefront wall 34 of the casing is provided with a horizontally extendingrectangular opening which I have shown fitted with a transparent window44, held in position between an outer bezel-moulding 45 and an innerrimplate 46 having a hooded view-opening 41, and that the pointer 36projects downwardly into view and is movable from side to sideimmediately back of said window. Now, when one of the indicator scalesis displayed back of said pointer, in the manner I shall describe, theentire scale may be viewed through window 44 and view-opening 41 and theposition of the pointer with respect to the divisions of said scaleeasily observed and followed in the adjustment of the apparatus. Acomplete turn of the tuning knob 35 will effect but a fractionaladjustment of the tuning condenser 2, and such fractional adjustment ofthe condenser will be represented by a substantial movement of theindicator pointer 36 along the indicator scale, thereby enabling aprecise and minute tuning adjustment to be made and accuratelyindicated.

The present arrangement employs three indiand 50, of which scale 48 isfixed in position back of pointer 36 and extends horizontally the fulllength of view-opening 41, scale 49 is pivotally supported to permit itto be swung into and from a position closely in front of scale 48, andscale 50 is pivotally supported to permit it to be swung into and from aposition closely in front of scale 49. Preferably, but not necessarily,the three indicator scales zontally extending axis, indicated at 5|(Fig. 4) and the downwardly projecting pointer 36 is curved to parallelthe curvatures of the scales, so that the space required between thepointer and scale 48 to permit the movement and interpositioning of thescales 49 and 50 is minimized. The cylindrical curvature of the scalesthroughout their length also serves to stiffen them, permit them to beformed of thin material, and prevent warping or distortion thereof, suchas might cause them to interfere or rub together during movement of thescales 49 and 50 into and from the positions described, and such asmightalso interfere with the lateral movement of pointer 36 along thescales.

Obviously, the scales may be of any suitable material and the scalemarkings may be etched, printed, or otherwise displayed thereon. Iprefer to form them of thin sheet metal, pressed to provide thecylindrically curved faces and having the end parts bent rearwardly toform the seg- 2,330,818 Scale 48 is fixed ment-shaped supporting arms.in position by securing the arms 52 and 53 thereof to the bearing-plates9 and I0, respectively, as by fiush rivets 54 (Figure 1), and scales 49and 58 are each pivotally supported by mounting their arms 55, 56, and51, 58, respectively upon stubshafts 59 and 58 fixed upon saidbearing-plates in positions co-axial with the aforesaid axis 5|. Arms55, 58, 51 and 58 are provided with respective hub-bearings 6|, 82, 83and 64, (Fig. 2), to properly space the arms from each other and frombearing-plates 9 and I8, and these hubbearings are retained in closearrangement upon stub-shafts 59 and 58 by respective end washers 65 andcotter-pins 68 in a manner to permit free pivotal movement ofthe scalesupon the stub shafts and prevent lengthwise displacement of the scaleswith respect to pointer38.

Referring, now, more particularly-to Figures- 3 and 4, it will be seenthat arm 58 of scale 49 extends rearwardly, as indicated at 61, beyondits pivotal support upon stub-shaft 88 and is pro vided near its freeend with a short laterally extending stud 68carrying an anti-frictionroller 69. Arm 58 of scale 58 also extends rearwardly, as indicated at10, beyond its pivotal support upon apparatus for use in any one ofthree frequency bands.

In Figure 1, I have shown a three-position dctent device 83 and athree-point band switch 84 operatlvely connected with a shaft 85 whichis rotatably supported near its rearward end in member of the drop frame26 and near its forward end in the front vertical wall 32 of chassis I.A crank-arm 88 is secured upon the rearward end-part of shaft 85 and acrank-arm 81 is secured upon the forward end-part thereof. The crank-arm86 is connected by a link 88 with the operating arm 18 of rocker I6 andthe crank-arm 81. is connected by a link 89 with a crank-arm 98 securedupon a hollow shaft 9| mounted as a sleeve upon the shaft 3|. Theforward end of shaft 9| projects through the frontwall 34 of the casingand is provided with a manually operable lever 92 secured thereupon.

The detent device 83 comprises a pair of fiat circular plates 93 and 94arranged closely parstub-s haft 68 and is provided near its free endwith a short laterally extending stud II carrying an anti-frictionroller 12. As shown clearly in Figures 2 and 4, the rearward extensionI8 of arm 58 is given an offset bend I3 and the studs 68 and II projecttoward each other at equal radial distances from the stub-shaft 88.

Bearing-plate I 8 is formed with a rearwardly extending arm I4, and alaterally extending stubshaft I5 is fixed upon the end-part of said arm.Rotatably mounted upon stub-shaft I5 is a rocker I6, which isoperatively connected with the band switch and acts in a manner to bedescribed to transmit movement therefrom to the movable indicator scales49 and 58 and effect their proper selective operation. Rocker 18comprises a for- -wardly extending sector-plate "having a rearwardlyprojecting operating arm I8 secured upon a hub I9 which is rotatablymounted upon stubshaft 15 and retained thereupon by a cotter-pin 88. Aplate 8| is secured upon the side of sectorplate TI in spaced parallelarrangement along the upper radial edge-part thereof. Sector-plate I1 ispositioned to engage the anti-friction roller 89 upon the stud 68 of arm56 of scale 49, and plate 8| is positioned to engage the anti-frictionroller 12 upon the stud II of arm 58 of scale 58, With the several partsin the positions shown in Figure 4, the operating arm 18 of rocker I8 islow.- ered and sector-plate 11 is raised, and the two indicator scales49 and 58 are both allowed-to I rest against a bumper or stop 82 andexpose fixed indicator scale 48. N

The manually operable mechanism for selec tively conditioning theapparatus for operation in a desired frequency band, and forautomatically bringing the proper indicator scale for that band intoview, will now be described. Since the present invention may be employedwith various selective circuit arrangements and is not limited to anyone in particular, no circuit arrangement has been shown. The use ofthree indicator scales has been described, and a conventional form ofthreepoint band switch will be described for use in connectiontherewith, it being understood that the radio receiving apparatus inthis instance comprises three circuits connected with the band switchfor selectively conditioning the allel with each other andconcentrically about shaft 85. Plate 93 is provided with, or fixed upon,a threaded, hub-bushing 95, which constitutes a bearingfor shaft 85 andis clamped firmly to vertical wall 32 of chassis I by hub-nut 96,whereby plate 93 is held from turning with said shaft. Plate 94 is ofspring-material fixed upon a hub 91 which is secured upon said shaft, asby pin 98, and turns therewith. Plate 93 is formed with a series ofarcuately arranged projecting knobs or ridges 99, and plate 94 is formedwith one or more ball-sockets I88, each having a ball |8| seated thereinand held by the ball-retaining plate I82. As shaft 85 is rotated, plate94 will be rotated thereby'with respect to plate 93 and the balls I8|will be rolled over the projecting knobs orridges 99, thespring-mtaerial of plate 94 permitting such rotation and causing astep-by-step adjustment of the shaft as the ballsare rolled over saidknobs or ridges and down into the valleys therebetween.

The band switch 84 comprises a supporting plate I83 which is secured toand dependsfrom the top of chassis Shaft 85 passes through an openingI84 in said plate. and a collar I85 of insulation-material is fixed uponsaid shaft close to said opening. 'An arcuate contact plate I06, havingan extending finger I81, is secured upon collar I85. An arcuate plateI88 of insulationmaterial is fixed upon supporting plate I83, and fourspring contact fingers I89, H8, III and 2, are secured to plate I88 withtheir free ends projecting radially inwards toward shaft 85. Contactfinger I89 reaches inwardly and contacts plate I88, while contactfingers III], III and I I2 do not extend far enough to contact the bodyof the plate, but are arranged to be contacted by finger I81 thereof insequence as shaft 85 is rotated. A lead from the tuning circuit of theapparatus may be connected with contact finger I89, and separate leadsfrom the inductance windings corresponding to different frequency orwave bands may be connected with contact fingers III), III and H2. Inthe present instance, the several contact fingers III), III and 2represent the separate circuits employed in tuning the apparatus for therespective frequency bands represented by the three indicator scales 58,49 and 48.

With the manually operable lever 92 in its leftward position, asindicated in dotted lines in Figure 2, shaft 85 will be in the positionshown in Figures 1 and 4, in which finger I87 will con- 48 will beexposed to view. Shaft 85 will be retained in this {position by theaction of detent device 83. For the purpose of this explanation,

it may be assumed that this position of the band switch 84 places theapparatus in condition for operation within the broadcast band offrequencies, and that the exposed indicator scale 48 is provided withthe proper scale markings for broadcast band tuning.

Counter-clockwise movement of lever 92 from its leftward position to itsintermediate position will partially turn shaft 9| and crank-arm 90 and,through link 89 and crank-arm 81, will partially rotate shaft 85 andplate 94 of the detent device 83 to roll the balls IOI over the first oftheir respective series of knobs or ridges 99 and down into the valleysbetween the first and second of said knobs or ridges, and the parts willbe held in their newly adjusted positions by the action of spring-plate94 upon the balls IOI in the well-known manner. This one-step adjustmentof shaft 85 will shift the contact finger I01 of band switch 84 from itsengagement with spring contact finger II2 into engagement with thefinger III and thereby condition the apparatus for operation in adifferent frequency or wave band, and will simultaneously partially turncrank-arm 86 and, through link 88 and arm 18, will partially turn rocker16 to force sector-plate 11 down against roller 69 of stud 68 on therearward extension 61 of arm 56 of scale 49 and move scale 49 up infront of scale 48, where-it will be viewable through window 44 andviewopening 41. Due to the divergence of the paths traversed bysector-plate I1 and arm 61, this movement will cause the lower edge ofthe sector-plate to move off from and past roller 89, and the forwardarcuate edge of the sector-plate will be substituted therefor (seeFigure 3), in whichposition the forward edge of the act upon roller 69to retain scale 49 in its raised position while permitting furtherpartial turning of rocker 16 in the second step of its adjustment nextdescribed. Scale 49 is provided with the proper scale markings fortuning in the frequency or wave band for which the apparatus is nowconditioned. 7

Further counter-clockwise movement of lever 92 from its intermediateposition to its rightward position will effect a second step adjustmentof shaft 85 in the manner just described; roll the balls IUI of thedetent device 83 up and over the second of their respective series ofknobs or sector-plate will ridges 99 and down into the valleys betweenthe second and third of said knobs or ridges, where they will be held bythe action thereupon of the springplate 94; shift the contact finger I81into engagement with spring contact finger III], and

thereby effect the conditioning of the apparatus for operation inanother frequency or wave band; and will simultaneously effect a furtherpartial turn of rocker 16 in the manner previously described. Thisfurther turn of rocker 16- will force the plate 8I. down. against roller12 of stud 1| on the rearward extension 10 of arm 58 of scale 50 andmove scale 58 up in front of I scales 48 and 49, where it be viewablethrough window 44 a'nd'view-opening 41. During this second step partialturn of rocker 16, the forward arcuate edge of sector-plate 11 will movealong against the roller 69 On stud 88 to hold the scale 49 in itsraised position without increasing the resistance of the second stepoperation by adding its weight to that of scale 51!; It may be assumedthat this second step adjustment of the band switch places the apparatusin condition for operation within the short wave band of frequencies,and that the scale 50 is provided with the proper scale markings forshort wave band tuning.

The reverse operation of lever 92 and the parts connected therewith istoo simple and obvious to need detailed description. It is sufficient tostate that clockwise movement of lever 92 from its rightward position toits intermediate position will shift contact finger I01 from springcontact finger H8 into engagement with finger II I, and raisesector-plate 11 and plate 8| sufliciently to permit scale 50 to returnto rest against stop 82 and expose scale 49, as shown in Figure 3 of thedrawings, and that further clockwise movement of lever 92 from itsintermediate to its leftward position will shift contact finger I01 fromspring contact finger III into engagement with finger H2, and furtherraise sector-plate 11 to permit scale 49 to return to rest against stop82 and expose fixed scale 48, as illustrated in the other figures of thedrawings.

A bumper H3 is secured by a screw II4 upon each of the upwardlyextending arms I6 to extend over the side arms 55, 5B, 51 and 58 as aguard against possible overthrow and/0r disarrangement of the scales 49and-50, such as might otherwise be occasioned by rough transportation orhandling of the apparatus.

I claim:

1. Indicator mechanism comprising a plurality of longitudinallyextending scales, each having scale indicia displayed upon the frontface thereof, one of eaid scales being supported for movement in acylindric path, and manually operable means operatively associated withsaid one of said scales acting upon operation to effect its movementinto and from a position in front of another of said scales.

2. Indicator mechanism comprising a plurality of longitudinallyextending scales, each having scale indicia displayed upon the frontface thereof, one of said scales being supported for movement in acylindric path, an indicator supported for movement lengthwise of saidscales to traverse the scale indicia displayed thereupon,andmanuallyoperable means operatively associated with said one of saidscales acting upon operation to effect its movement into and from aposition between said indicator and another of said scales.

3. Indicator mechanism comprising a plurality of longitudinallyextending scales, each having scale indicia displayed upon the frontface thereof, one of'said scales being supported for movement in acylindric path, a wall -arranged in front of said scales having alongitudinally extending opening through which the scale indicia uponsaid scales may be viewed, and manually operable means operativelyassociated with said one of said scales acting upon operation to effectits movement into and from a position bewall and another of said scales.

4. Indicator mechanism comprising a plurality of longitudinallyextending scales, each having scale indicia displayed upon the frontface thereof, one of said scales being supported at each end thereof toswing in a cylindric path upon an axis parallel to the face thereof, andmanually operable means operatively associated with said one of saidscales acting upon operation to effect its swinging movement into andfrom a position in front of another of said scales.

scale indicia displayed upon the front face therea of, certain of saidscales being supported for movement in cylindric paths upon a commonaxis, and manually operable means operatively associated with saidcertain of said scales acting upon operation to effect their successivemovement into and their successive movement from a position in front ofanother of said scales.

7. Indicator mechanism comprising a plurality of longitudinallyextending scales, each having scale indicia displayed upon the frontface thereof, one of said scales being supported in fixed position andothers of said scales being supported for movement in cylindric pathsupon a common axis, and step-by-step manually operable meansoperatively'associated with said others of said scales acting upon onestep of its operation to effect the movement of one thereof into aposition in front of said fixedly supported scale and retain it in suchposition, and upon another step of its operation to efiect the movementof another one thereof into a position in front of the scale previouslymoved into and retained in its aforesaid position.

- KURT EMDE.

